Rotational armrest apparatus

ABSTRACT

A chair includes a seat and a rotational armrest apparatus mounted on the seat. The armrest apparatus includes a beam attached to the seat and an armrest rotationally mounted on the beam. The beam includes a socket formed thereon. The armrest includes a lower portion inserted rotationally in the socket and an upper portion for supporting an arm. The beam defines apertures through which fasteners can be driven into the seat for mounting the beam on the seat. The socket defines an upper space and a grooved recess communicated with the upper space. The lower portion of the armrest includes a toothed insert inserted in the grooved recess for retaining the armrest in position relative to the beam.

FIELD OF INVENTION

[0001] The present invention relates to a chair and, more particularly, to a rotational armrest apparatus of a chair.

BACKGROUND OF INVENTION

[0002] A typical chair for use in an office includes a base, a post mounted on the base, a seat mounted on the post, a backrest mounted on the seat and two armrests mounted on the seat. Some armrests are retained in position relative to the seat. Some other armrests include a telescopic structure that can be lifted or lowered according to a user's size. However, no armrest has come to the applicant's knowledge that is rotational relative to the seat.

SUMMARY OF INVENTION

[0003] The primary objective of the present invention is therefore to provide a chair with a rotational armrest apparatus.

[0004] According to the present invention, the armrest apparatus includes a beam attached to the chair and an armrest rotationally mounted on the beam.

[0005] The beam includes a socket formed thereon. The armrest includes a lower portion inserted rotationally in the socket and an upper portion for supporting an arm.

[0006] The beam defines apertures through which fasteners can be driven into the seat for mounting the beam on the seat. The socket defines an upper space and a grooved recess communicated with the upper space. The lower portion of the armrest includes a toothed insert inserted in the grooved recess for retaining the armrest in position relative to the beam.

[0007] Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the attached drawings.

BRIEF DESCRIPTION OF DRAWINGS

[0008] The present invention will be described via detailed illustration of embodiments referring to the drawings.

[0009]FIG. 1 is a perspective view of a rotational armrest apparatus including a beam for attachment to a seat and an armrest rotationally mounted on the beam according to a first embodiment of the present invention.

[0010]FIG. 2 is an exploded view of the rotational armrest apparatus shown in FIG. 1.

[0011]FIG. 3 is a cross-sectional view taken along a line 3-3 in FIG. 1.

[0012]FIG. 4 is a cross-sectional view taken along a line 4-4 in FIG. 1.

[0013]FIG. 5 is an enlarged cross-sectional view taken along a line 5-5 in FIG. 1.

[0014]FIG. 6 is similar to FIG. 3 but showing a lock in a different position.

[0015]FIG. 7 is similar to FIG. 4 but showing a toothed insert moved from a grooved recess.

[0016]FIG. 8 is similar to FIG. 6 but showing the armrest in rotation.

[0017]FIG. 9 is a perspective view of a rotational armrest apparatus including a beam for attachment to a seat and an armrest rotationally mounted on the beam according to a second embodiment of the present invention.

[0018]FIG. 10 is a cutaway view of the rotational armrest apparatus shown in FIG. 9.

[0019]FIG. 11 is similar to FIG. 10 but showing the armrest locked in position relative to the beam.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0020] Referring to FIG. 1, according to the preferred embodiment of the present invention, a rotational armrest apparatus 1 includes a beam 10 for attachment to a seat of a chair (not shown) and an armrest 20 rotationally mounted on the beam 10.

[0021] The beam 10 includes a socket 12 formed thereon. The armrest 20 includes a lower portion in the form of an insert 22 rotationally inserted in the socket 12 and an upper portion 21 for supporting an arm.

[0022] Referring to FIG. 2, the beam 10 defines slots or apertures 11 through which fasteners (not shown) can be driven into the seat for mounting the beam 10 on the seat. The socket 12 defines a space 13, a taper recess 14 communicated with the space 13 and a space 17 communicated with the grooved recess 14. Grooves (not numbered) are defined in the recess 14. An annular shoulder 15 is formed on the external side of the socket 12. Two grooves 16, two recesses 161 and two apertures 162 are defined in the external side of the socket 12. Each of the grooves 16 becomes deeper from a first end to a second end. Each of the recesses 161 is communicated with one of the grooves 16 at the first end. Each of the recesses 161 is deeper than the first end of each of the grooves 16. Via each of the apertures 162, the second end of one of the grooves 16 is communicated with the space 13.

[0023] The insert 22 includes a taper end 23 formed with a plurality of teeth (not numbered), a threaded hole 24 defined in the taper end 23 and an annular groove 25 defined therein above the taper end 23.

[0024] A lock 30 is in the form of a ring. The lock 30 includes two detents 31 projecting from the internal side and each including an enlarged head 32. The lock 30 includes a plurality of ribs 33 extending on the external side in order to facilitate rotation of the lock 30.

[0025] In assembly, the lock 30 is mounted on the socket 12, with its lower annular edge resting on the annular shoulder 15. The detents 31 are put in the grooves 16. The insert 22 of the armrest 20 is inserted in the socket 12. The taper end 23 is put in the taper recess 14. The heads 32 enter the annular groove 25 through the apertures 162. A spring 26 and a cap-shaped washer 27 are put in the space 17. A threaded bolt 28 is driven into the threaded hole 24 through the washer 27 and the spring 26.

[0026] Referring to FIGS. 3-5, the taper end 23 is put in the taper recess 14 so that the teeth formed on the taper end 23 are inserted in the grooves defined in the taper recess 14. Thus, the armrest 20 cannot be rotated on the beam 10. The heads 32 are in the annular groove 25. Thus, the taper end 23 cannot be moved from the taper recess 14, i.e., the armrest 20 cannot be rotated on the beam 10.

[0027] Referring to FIG. 6, the lock 30 is rotated relative to the socket 12. The heads 32 are moved from the annular groove 25 through the apertures 162. Further, the heads 32 are moved into the recesses 161 through the grooves 16, and kept there. Referring to FIG. 7, the taper end 23 is moved from the taper recess 14 so that the teeth formed on the taper end 23 are moved from the grooves defined in the taper recess 14. Thus, the armrest 20 can be rotated on the beam 10 as shown in FIG. 8.

[0028]FIG. 9 shows a rotational armrest apparatus 2 according to a second embodiment of the present invention. The rotational armrest apparatus 2 is identical to the rotational armrest apparatus 1 except for several aspects. Firstly, the lock 30 is deleted from the rotational armrest apparatus 2. Hence, the grooves 16, the recesses 161 and the apertures 162 are deleted from the socket 12, and the groove 25 from the armrest 20. Secondly, the taper end 23 is replaced with a flat end 29. Hence, the taper recess 14 is replaced with a flat recess 19.

[0029] Referring to FIG. 10, the threaded bolt 28 slacks in the threaded hole 24. The flat end 29 is outside the flat recess 19 so that the teeth formed on the flat end 29 are outside the grooves defined in the flat recess 19. Thus, the armrest 20 can be rotated on the beam 10.

[0030] Referring to FIG. 11, the threaded bolt 28 is tightly driven into the threaded hole 24. The flat end 29 is inserted in the flat recess 19 so that the teeth formed on the flat end 29 are inserted in the grooves defined in the flat recess 19, thus avoiding rotation of the armrest 20 relative to the beam 10.

[0031] The present invention has been described via detailed illustration of the preferred embodiment. Those skilled in the art can derive many variations from the preferred embodiment without departing from the scope of the present invention. Therefore, the preferred embodiment shall not limit the scope of the present invention defined in the claims. 

What is claimed is:
 1. A chair including a seat and a rotational armrest apparatus mounted on the seat.
 2. The chair according to claim 1, wherein the armrest apparatus includes a beam attached to the seat and an armrest mounted rotationally on the beam.
 3. The chair according to claim 2, wherein the beam includes a socket formed thereon, and the armrest includes an insert rotationally inserted in the socket and an upper portion for supporting an arm.
 4. The chair according to claim 2, wherein the beam defines apertures through which fasteners can be driven into the seat for mounting the beam on the seat.
 5. The chair according to claim 2, wherein the socket defines an upper space and a grooved recess communicated with the upper space, and the insert of the armrest includes a toothed tip inserted in the grooved recess for retaining the armrest in position relative to the beam.
 6. The chair according to claim 5 including a threaded bolt, wherein the toothed tip defines a threaded hole receiving a threaded bolt with a head so as to retain the armrest on the beam, and the socket defines a lower space communicated with the grooved recess for receiving the head of the threaded bolt.
 7. The chair according to claim 6 including a spring put in the lower space, mounted on the threaded bolt and compressed between the wall of the lower space and the head of the threaded bolt for keeping the toothed tip in the grooved recess.
 8. The chair according to claim 7 including a washer put in the lower space and sandwiched between the spring and the head of the threaded bolt.
 9. The chair according to claim 8 including the washer is shaped as a cup for receiving the spring.
 10. The chair according to claim 5 including a lock for locking the toothed tip in the grooved recess.
 11. The chair according to claim 10, wherein the lock is in the form of a ring rotationally mounted on the socket between a locking position and a releasing position.
 12. The chair according to claim 11, wherein the lock includes at least one detent extending from an internal side, and the socket defines at least one aperture through which the at least one detent enters the upper space, and the insert of the armrest defines at least one annular groove for receiving the at least one detent.
 13. The chair according to claim 12, wherein the lock includes two detents, and the socket defines two apertures, and the insert of the armrest defines an annular groove for receiving the detent.
 14. The chair according to claim 12, wherein the socket defines, in an external side, a groove including a first end and a second end where the aperture is located and getting deeper from the first end to the second end.
 15. The chair according to claim 12, wherein the detent includes an enlarged head.
 16. The chair according to claim 15, wherein the socket defines, in an external side, a recess for receiving the head of the detent in the releasing position.
 17. The chair according to claim 11 wherein the lock includes ribs formed thereon for facilitating rotation thereof. 